The present invention relates to a non-aqueous type resin useful for a developer for electrostatic photography, particularly toner for color copy, paints, adhesives, printing inks, dispersion polymers for magnetic materials, and the like.
Examples of conventional well known polymerizable monomers having polar groups include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, hydroxyethylacrylate, hydroxyethylmethacrylate, glycidylmethacrylate and the like. Polar groups of these polymerizable monomers cause ionic dissociation in an aqueous solvent and the dispersion stability of pigments is improved. However, the ionic dissociation is not caused in a non-aqueous solvent such as a liquid developer for electrophotography (e.g. isoparaffin) and the electric charge of polymer does not appear. Therefore, it was difficult to control the electric charge for color pigment particles. In such a case, a method for ionizing a carboxyl group with base was employed, but it was difficult to make a balance of acid-base and therefore stable electric charge could not be maintained.
Many of toners used for a developer generally have a particle size distribution of 0.3-1.0.mu.. A color toner having a smaller particle size and a narrower particle size distribution has been desired.